Maybe at some point when the technology has been perfected, offers considerably dynamic range, and reaches around 500DPI such that the visual acuity of someone with 20/10 vision can't see any pixels...then they might be ready to replace OVFs en-masse.

ok... but i am typing this on an ipad with a 264ppi density, the Galaxy X IV phone is 440, 500 isn't too far in the future

You need a much higher PPI than 500. These displays are tiny. Epson have just announced a sub one megapixel display (1024x768, only one quarter of the pixels found on a retina iPad display) to equal Sonys top of the line OLED viewfinder. It's diagonal measurement is 0.48 inch. That 2666 PPI. We need much more than that to make it lifelike.

Are 1200 or 2600 ppi EVF's in use in consumer-grade cameras today? And it seems my calculation was wrong before for the required PPI. We can derive the necessary PPI using a little math, though... If I use the visual acuity for a person with 20/10 vision (which for most people with corrective lenses these days is the case, including glasses, hard contact lenses, and for the most part soft contact lenses), we have 0.7 arc seconds, or 1/86th of a degree (normal 20/20 vision is about 1 arc second, or 1/60th of a degree). Turning degrees into a scalar distance and computing for resolving power:

tan(A) = opp/adjtan(deg) = size_of_pixel/distance_to_screentan(1/86) * distance_to_screen = size_of_pixelIf we assume a one inch distance from the eye to the EVF, resolving power of the eye (the smallest resolvable detail in inches) would be:

1"/P = 1"/0.0002" = 5000PPIThat assumes a 1" viewing distance, or a fairly standard 25mm. There are cameras with smaller viewfinder eye relief than that...some as small as 10-11mm. To account for that:

PPI = 1"/(P*D)1"/(0.0002" * 0.43") = 11,268PPIA 2600ppi display would definitely be getting there for 20/20 vision and a 1" relief, but if my calculations above are correct...for 20/10 vision we would really need 5000ppi (O_o...sorry, I guess I dropped a zero somewhere before) and a 1" relief. If viewfinder eye relief is smaller than 1", then for 20/10 vision we might need as high as 12,000PPI!!! (Is that even possible? Each RGB pixel would have to be 2.1 microns in size, each subpixel element would be 0.7 microns, or 700nm, in size...at that size we are getting down to the wavelength of red light!!)

Assuming there are consumer-grade EVF's with 1200ppi or even 2666ppi, what are the refresh rates like? Color depth? I'd read several things about Sony EVF's clipping blacks or producing poor tonal range in the shadows. As far as I knew, that was Sony's latest and greatest EVF, but I could be wrong. That just demonstrates some of the DR problems I'm worried about though...you simply don't have ANY issues like that with an OVF. About the only issue I can think of with an OVF is the potential for blinding yourself in one eye if you look at the sun through the lens...but, well, that's operator error. ;P

Pixel density (and I mean full RGB pixel density, so 5000ppi would be the lower end limit as far as I am concerned) is only one factor. You still need to improve the dynamic range and color depth of such displays, improve their refresh rate, etc.

There are also other caveats that come into play with EVF's that have nothing to do with the design of the viewfinder screen. When it comes to low-light photography, the quality of the rendered image will drop, as you have to use the image sensor, with all of its limitations and flaws, to record the light coming through the lens. You'll experience increasing noise and banding as sensitivity cranks up to compensate for lower light. With an optical viewfinder, your eyes will do the adjusting for low light after a short while, and are far more adept at seeing in low light than an electronic image sensor could ever hope to be. I'd never be able to do night sky photography with an EVF...even with the large LCD screen on my 7D, I can't see anything except the brightest stars, and when cranking up ISO you still don't see any more as noise starts to take over and drowns everything out. I have to let my eyes adjust to the dark, but when they do, I can see hundreds of stars through the optical viewfinder, frame and focus my shots, etc.

I could probably keep going...the limitations of EVF's vs. an optical viewfinder are considerable, and many of them are not just due to the design of the viewfinder screen itself, some are due to the limitations in sensor sensitivity. The limitations of the sensor extend into other areas of mirrorless technology...for example low-light AF. FP-PDAF pixels in mirrorless sensors are moderately capable in good light, but they are part of the sensor. Image sensors are orders of magnitude less sensitive to light than specially designed phase detection AF sensors. The kind of low-light AF capabilities we enjoy today with -2EV and in some cases even -3EV AF without an AF assist light are at the very least years ahead of FP-PDAF, and given the nature of image sensors, which must be primarily tuned for a different purpose (capturing quality images), I wonder if FP-PDAF will ever be quite as good as a dedicated AF unit in a DSLR.

Sure, I think progress is good, and I think the diversification of options is also good. However, mirrorless technology is premature for widespread use and replacement of DSLR tech. I'd say radically premature for use in professional grade mirrorless cameras that could potentially replace DSLRs...at least at current DSLR prices (one could always spend $50 grand on some kind of top of the line mirrorless with all the bells and whistles if they really want something mirrorless that will service modern professional photography needs, assuming such an offering is made available.)

And the number of pixels you're on about sounds to be about right for something that has enough resolution to look perfect to anyone. However, with anything but the largest EVF, I guess iPad retina resolution would suffice for most people?

That one is about 2645ppi. Slightly better than the Sony one, but only about 50% of the pixel density I'd say is required for EVF's to be ready for use in a broad sense in a much broader base of mirrorless offerings that might potentially be capable of replacing DSLRs.

And the number of pixels you're on about sounds to be about right for something that has enough resolution to look perfect to anyone. However, with anything but the largest EVF, I guess iPad retina resolution would suffice for most people?

The iPad Retina resolution is 264ppi, intended for viewing at arms length. Remember, visual acuity is distance-dependent. At 12-15 inches viewing distance, of course a mere 260ppi is enough. The iPhone retina resolution is about 326ppi, intended for viewing around 6 inches. With an EFV, we are talking about viewing at 1/2" to 1" distance...you need a hell of a lot more pixels far more densely packed to push past the visual acuity boundary. If you only aim to meet 20/20 vision, all the people like myself end up SOL, being able to clearly see pixels (which, BTW, I can clearly see iPad retina pixels, and I can see iPhone retina pixels, as well as my new Lumia 920 pixels which clock in at about 330ppi, most of the time.)

If we assume manufacturers are aiming just to meet the minimum acuity requirements for those with 20/20 vision, they still need to reach 3448ppi. At 2666ppi, your about 30% short of the bare minimum target where the average person couldn't see pixels on a regular basis at 1" eye relief. At a 1/2" eye relief, you need 6900ppi. A lot of people stick their eye snugly right into the viewfinder eyepiece, moving it even closer. For the average person to see no pixels on an EVF, you still need about 5000ppi. I think that is the break-even point where EVF's start to get good enough for general use...5000ppi should be more than good enough for the average person, and just good enough for someone with high visual acuity, for a standard 1" viewing distance. If viewing distance shrinks (which is often the case for current mirrorless cameras in smaller form factors), 5000ppi is still not enough for the average person.

I purchased my 7D on the first day of availability at full MSRP. Did not regret it for a single moment. It is an amazing camera. Still love to use it today.

By now, I would happily buy a 7D Mk. II with the following improvements:* current state of the art sensor, at least on par with Sony/Nikon sensors, especially as far as DR is concerned: +2 stops DR and +2 stops in Hi ISO, meaning, ISO 6400 behaving like ISO 1600 on 7D. And ultra-clean ISO 100. * 18 MP are enough for me, but up to 24 MP would be fine too, since I do have lenses to match * AF further improved, ideally in via a really fast hybrid CD-AF + in-sensor Phase-AF * WiFi build in, GPS built in* wireless EX-RT flash transmitter built in * retain pop-up flash / optical master * touch screen LCD, fully articulated!* significantly better new generation battery packs ... with higher energy density like on Hero GoPro 3* locking mode wheel [as on 5D III] with 4 Custom Mode Settings* price not higher than 7D MSRP ... USD/€ 1700

That alone would make it a sure winner.If Canon had any marketing genius working for them, they would just go ahead and bring it in two versions - DSLR AND mirrorless - with exactly the same specs, performance and functionality [except OVF vs. EVF and loss of regular phase-af on the mirrorless version] and at exactly the same price. :-)

7D Mk. II DSLR - size, weight, shape exactly like 7D, again with 100% OVF and regular Phase-AF in addition to hybrid-AF [CD-AF+ in-sensor PD-AF ... only used in live view]

EOS-M7mirrorless, size, weight, shape very similar to EOS-M ... only slightly larger due to brilliant, state-of-the-art EVF. Loss of mirror-dependent Phase-AF but still 80% AF speed and performance with hybrid AF system. EF-M mount, further improved kit-lens, plus a few pancake fixed focals. All EF-S and EF-lenses fully functional via existing EOS-M adapter.

I would take the mirrorless version, because I always wanted only one camera with only one ergonomic layout to use "ultralight" for travel, mountainieering and street photography ... and to use "like a DSLR" for specific tasks, where size & weight do not matter e.g. because large lenses and/or tripod are required anyway.

Within a few months all Canon, its competitors and all of us would finally know for sure, where customers stand on DSLR vs. mirrorless.

I personally do not see what they are waiting on. IMO they have the best lenses in the business. As a birder I do not want the 1dX or i would buy one. The new lenses are superb. The 7D just does not have the AF to make these big lenses shine anymore. If they come out with a pro-body crop in 1.5-1.6 they will rule the world. Hands down.Just amazing to me they do not act? They would have hit on there hands like the old 5d II I think. It would make them millions.

just read another bit of japanese translation interview and it's typically vague, even on top of the usual japanese language + pre-show ambiguity.saying the 7d2 isn't the story of the day likely means it's not going to show up at CP+or..it could mean something else will hilite the event (new sensor tech?) which may eclipse the 7d2 announcement which is alleged to be an incremental upgrade over the 7d.

We'll know what Canon wants to pry our wallets open with next soon enough.

just read another bit of japanese translation interview and it's typically vague, even on top of the usual japanese language + pre-show ambiguity.saying the 7d2 isn't the story of the day likely means it's not going to show up at CP+or..it could mean something else will hilite the event (new sensor tech?) which may eclipse the 7d2 announcement which is alleged to be an incremental upgrade over the 7d.

We'll know what Canon wants to pry our wallets open with next soon enough.

I agree with jrista about EVF's been a long way away from being truly good, but I also agree with your point that technology grows quickly, and it certainly will get there, probably sooner than the decade that jrista predicts.

One of my co-workers brought in an Olympus E-M5...we played comparison between it and a 7D. The EVF on it is comparable to the 7D, it takes better quality pictures in poor light, about the same in good light, and I really can't tell the difference in AF speed or accuracy. I was amazed that this camera was so good. It's hard to deny the existance of something you are holding in your hands... this wasn't just an EOS-M killer, it was a Rebel killer too, and if it wasn't for the way better user interface on the 7D and Canon Lglass, it would have topped the entire APS-C lineup.

And apparently Olympus has announced that the replacement for the E-5 will support both 4/3 and micro-4/3 lenses, which kind of implies that it will be micro-4/3 with an adapter. Nikon users are also complaining about there being no D400. My guess is that everybody is working on professional mirrorless cameras and that the 7D replacement will actually have the name "M1". When it comes is anybody's guess.

Something like the Metabones Speed Booster makes this possible.. That device has a magnification of 0.707 and gives a 1-stop improvement in maximum aperture. However, the Canon version of APS-C is 1.6X not 1.5X. Therefore, a Canon-specific booster could have a magnification of 0.629 and give a 1-1/3 improvement in maximum aperture.